The blast could be heard across the Yemeni capital and a large plume of smoke could be seen, according to Al Jazeera. In the aftermath, prone bodies were left lying amid twisted debris and recruits' discarded documents on the street, reports said.

Photos are pictured on the ground at the scene of a car bomb attack the police college in Sanaa Jan. 7.

Eyewitness Jamil al-Khaleedi told the Associated Press: "What happened is we were all gathering and ... (the bomber) exploded right next to all of the police college classmates. It went off among all of them, and they flew through the air."

No one has yet taken responsibility for the attack, but al-Qaeda in the Arabian Peninsula has targeted security forces several times in the past, the BBC said.

Yemen has been the scene of instability since anti-government protests in 2011 caused the downfall of strongman President Abdullah Saleh after 33 years in power in 2012.

Late last year, rebels from the Houthi group seized large portions of the country, including a number of government buildings in Sanaa.

Days of heavy fighting between the Houthis and government forces ended with a fragile peace agreement between the group and President Abd Rabu Mansur Hadi, but tensions between the rival factions in the country remain.